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This patch adds support for the Xilinx plbv46-pci-1.03.a PCI host
bridge IPcore.
Signed-off-by: Roderick Colenbrander <thunderbird2k@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
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It was __devinit, but it is also within a CONFIG_HOTPLUG guarded section
of code, so the __devinit does nothing but cause the following warning:
WARNING: vmlinux.o(.text+0x107a8): Section mismatch in reference from the function pcibios_finish_adding_to_bus() to the function .devinit.text:pcibios_claim_one_bus()
The function pcibios_finish_adding_to_bus() references
the function __devinit pcibios_claim_one_bus().
This is often because pcibios_finish_adding_to_bus lacks a __devinit
annotation or the annotation of pcibios_claim_one_bus is wrong.
It is also only (externally) used in arch/powerpc/kernel/of_platform.c
which cannot be built as a module so don't export it.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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There's no need to wrap PPC_INST_NOP in a static inline.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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These macros were used in the original port, but since commit
e4486fe316 (ftrace, use probe_kernel API to modify code) they
are unused.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Use ppc_function_entry() from code-patching.h.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch updates the output from /proc/ppc64/lparcfg to display the
processor virtualization resource allocations for a shared processor
partition.
This information is already gathered via the h_get_ppp call, we just
have to make sure that the ibm,partition-performance-parameters-level
property is >= 1 to ensure that the information is valid.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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RTAS event scan has to run across all cpus. Right now we use a kernel
thread and set_cpus_allowed but in doing so we wake up the previous cpu
unnecessarily.
Some ftrace output shows this:
previous cpu (2):
[002] 7.022331: sched_switch: task swapper:0 [140] ==> rtasd:194 [120]
[002] 7.022338: sched_switch: task rtasd:194 [120] ==> migration/2:9 [0]
[002] 7.022344: sched_switch: task migration/2:9 [0] ==> swapper:0 [140]
next cpu (3):
[003] 7.022345: sched_switch: task swapper:0 [140] ==> rtasd:194 [120]
[003] 7.022371: sched_switch: task rtasd:194 [120] ==> swapper:0 [140]
We can use schedule_delayed_work_on and avoid the unnecessary wakeup.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This bit would get enabled sometimes (probably after suspend/resume), so the
fan would run at full speed below the temperature thresholds, but slow down and
eventually stop if temperatures rose above the thresholds... not exactly what
you want.
Signed-off-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Do not go beyond ARRAY_SIZE of tape_device and viotape_unitinfo
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We can compile and boot with NR_CPUS=8192, so make this the max. 1024
was an arbitrary decision anyway.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin:
Blackfin: fix strncmp.o build error
Blackfin: drop unneeded asm/.gitignore
Blackfin: ignore generated vmlinux.lds
MAINTAINERS: drop (subscribers-only) markings on Blackfin lists
MAINTAINERS: update Blackfin items
Blackfin: hook up preadv/pwritev syscalls
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git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Fix up dma_alloc_coherent() on platforms without cache coherency.
powerpc: Minor cleanups of kernel virt address space definitions
powerpc: Move dma-noncoherent.c from arch/powerpc/lib to arch/powerpc/mm
Revert "powerpc: Rework dma-noncoherent to use generic vmalloc layer"
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Fix up renamed filenames in comments in fs/cachefiles/internal.h.
Originally, the files were all called cf-xxx.c, but they got renamed to
just xxx.c.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix up renamed filenames in comments in fs/fscache/internal.h.
Originally, the files were all called fsc-xxx.c, but they got renamed to
just xxx.c.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* 'for-linus' of git://neil.brown.name/md:
md: raid5: change incorrect usage of 'min' macro to 'min_t'
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A recent patch to raid5.c use min on an int and a sector_t.
This isn't allowed.
So change it to min_t(sector_t,x,y).
Signed-off-by: NeilBrown <neilb@suse.de>
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The implementation we just revived has issues, such as using a
Kconfig-defined virtual address area in kernel space that nothing
actually carves out (and thus will overlap whatever is there),
or having some dependencies on being self contained in a single
PTE page which adds unnecessary constraints on the kernel virtual
address space.
This fixes it by using more classic PTE accessors and automatically
locating the area for consistent memory, carving an appropriate hole
in the kernel virtual address space, leaving only the size of that
area as a Kconfig option. It also brings some dma-mask related fixes
from the ARM implementation which was almost identical initially but
grew its own fixes.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Make FIXADDR_TOP a compile time constant and cleanup a
couple of definitions relative to the layout of the kernel
address space on ppc32. We also print out that layout at
boot time for debugging purposes.
This is a pre-requisite for properly fixing non-coherent
DMA allocactions.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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(pre-requisite to make the next patches more palatable)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Fix some more fallout of the string changes:
CC arch/blackfin/lib/strncmp.o
In file included from include/linux/bitmap.h:9,
from include/linux/nodemask.h:90,
from include/linux/mmzone.h:17,
from include/linux/gfp.h:5,
from include/linux/kmod.h:23,
from include/linux/module.h:14,
from arch/blackfin/lib/strncmp.c:14:
include/linux/string.h: In function ‘strstarts’:
include/linux/string.h:132: error: implicit declaration of function ‘strncmp’
make[1]: *** [arch/blackfin/lib/strncmp.o] Error 1
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
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We don't create a include/asm/mach/ symlink anymore, so we don't need the
.gitignore for it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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All of the Blackfin lists are transparently moderated for non-subscribers.
i.e. there are no annoying notices and people get whitelisted after first
their posting.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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With Bryan Wu having moved on to another job, push the slack onto some
other ADI lackeys.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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This reverts commit 33f00dcedb0e22cdb156a23632814fc580fcfcf8.
While it was a good idea to try to use the mm/vmalloc.c allocator instead
of our own (in fact, ours is itself a dup on an old variant of the vmalloc
one), unfortunately, the approach is terminally busted since
dma_alloc_coherent() can be called at interrupt time or in atomic contexts
and there's little chances we'll make the code in mm/vmalloc.c cope with\ that :-(
Until we can get the generic code to forbid that idiocy and fix all
drivers abusing it, we pretty much have no choice but revert to
our custom virtual space allocator.
There's also a problem with SMP safety since freeing such mapping
would require an IPI which cannot be done at interrupt time.
However, right now, I don't think we support any platform that is
both SMP and has non-coherent DMA (don't laugh, I know such things
do exist !) so we can sort that out later.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
tomoyo: add missing call to cap_bprm_set_creds
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cap_bprm_set_creds() has to be called from security_bprm_set_creds().
TOMOYO forgot to call cap_bprm_set_creds() from tomoyo_bprm_set_creds()
and suid executables were not being working.
Make sure we call cap_bprm_set_creds() with TOMOYO, to set credentials
properly inside tomoyo_bprm_set_creds().
Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: avoid back to back on_each_cpu in cpa_flush_array
x86, relocs: ignore R_386_NONE in kernel relocation entries
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git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel:
drm/i915: Add support for VGA load detection (pre-945).
drm/i915: Use an I2C algo to do the flip to SDVO DDC bus.
drm/i915: Determine type before initialising connector
drm/i915: Return SDVO LVDS VBT mode if no EDID modes are detected.
drm/i915: Fetch SDVO LVDS mode lines from VBT, then reserve them
i915: support 8xx desktop cursors
drm/i915: allocate large pointer arrays with vmalloc
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
oprofile: fix cpu buffer size
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Cleanup cpa_flush_array() to avoid back to back on_each_cpu() calls.
[ Impact: optimizes fix 0af48f42df15b97080b450d24219dd95db7b929a ]
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFSv4: Fix the case where NFSv4 renewal fails
nfs: fix build error in nfsroot with initconst
XPRTRDMA: fix client rpcrdma FRMR registration on mlx4 devices
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: hda - Add missing check of pin vref 50 and others in Realtek codecs
ALSA: hda - Add 5stack-no-fp model for STAC927x
ALSA: hda - Add forced codec-slots for ASUS W5Fm
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git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] powernow-k8: determine exact CPU frequency for HW Pstates
[CPUFREQ] powernow-k8 cleanup msg if BIOS does not export ACPI _PSS cpufreq data
[CPUFREQ] fix timer teardown in ondemand governor
[CPUFREQ] fix timer teardown in conservative governor
[CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call
[CPUFREQ] powernow-k7 build fix when ACPI=n
[CPUFREQ] add atom family to p4-clockmod
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When KVM is loaded, and hence VT set up, the vmcall instruction in an
lguest guest causes a #GP, not #UD.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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call_usermodehelper_setup() forgot to kfree(sub_info)
when prepare_usermodehelper_creds() failed.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (21 commits)
r8169: avoid losing MSI interrupts
tcp: tcp_vegas ssthresh bugfix
mac8390: fix regression caused during net_device_ops conversion
gianfar: fix BUG under load after introduction of skb recycling
wimax/i2400m: usb: fix device reset on autosuspend while not yet idle
RxRPC: Error handling for rxrpc_alloc_connection()
ipv4: Fix oops with FIB_TRIE
pktgen: do not access flows[] beyond its length
gigaset: beyond ARRAY_SIZE of iwb->data
IPv6: set RTPROT_KERNEL to initial route
net: fix rtable leak in net/ipv4/route.c
net: fix length computation in rt_check_expire()
wireless: beyond ARRAY_SIZE of intf->crypto_stats
iwlwifi: update 5000 ucode support to version 2 of API
cfg80211: fix race between core hint and driver's custom apply
airo: fix airo_get_encode{,ext} buffer overflow like I mean it...
ath5k: fix interpolation with equal power levels
iwlwifi: do not cancel delayed work inside spin_lock_irqsave
ath5k: fix exp off-by-one when computing OFDM delta slope
wext: verify buffer size for SIOCSIWENCODEEXT
...
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git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc/mm: Fix broken MMU PID stealing on !SMP
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* 'for-linus' of git://neil.brown.name/md:
md: don't use locked_ioctl.
md: don't update curr_resync_completed without also updating reshape_position.
md: raid5: avoid sector values going negative when testing reshape progress.
md: export 'frozen' resync state through sysfs
md: bitmap: improve bitmap maintenance code.
md: improve errno return when setting array_size
md: always update level / chunk_size / layout when writing v1.x metadata.
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If the asynchronous lease renewal fails (usually due to a soft timeout),
then we _must_ schedule state recovery in order to ensure that we don't
lose the lease unnecessarily or, if the lease is already lost, that we
recover the locking state promptly...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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fix build error with latest kbuild adjustments to initconst.
The commit a447c0932445f92ce6f4c1bd020f62c5097a7842 ("vfs: Use
const for kernel parser table") changed:
static match_table_t __initdata tokens = {
to
static match_table_t __initconst tokens = {
But the missing const causes popwerpc to fail with latest
updates to __initconst like this:
fs/nfs/nfsroot.c:400: error: __setup_str_nfs_root_setup causes a section type conflict
fs/nfs/nfsroot.c:400: error: __setup_str_nfs_root_setup causes a section type conflict
The bug is only present with kbuild-next.
Following patch has been build tested.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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mlx4/connectX FRMR requires local write enable together with remote
rdma write enable. This fixes NFS/RDMA operation over the ConnectX
Infiniband HCA in the default memreg mode.
Signed-off-by: Vu Pham <vu@mellanox.com>
Signed-off-by: Tom Talpey <tmtalpey@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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Two approaches for VGA detections: hot plug detection for 945G onwards
and load pipe detection for Pre-945G. Load pipe detection will get one free
pipe, set border color as red and blue, then check CRT status by
swf register. This is a sync-up with the 2D driver.
Signed-off-by: Ma Ling <ling.ma@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
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Slightly modified by trenn@suse.de -> only do this on fam 10h and fam 11h.
Currently powernow-k8 determines CPU frequency from ACPI PSS objects, but
according to AMD family 11h BKDG this frequency is just a rounded value:
"CoreFreq (MHz) = The CPU COF specified by MSRC001_00[6B:64][CpuFid]
rounded to the nearest 100 Mhz."
As a consequnce powernow-k8 reports wrong CPU frequency on some systems,
e.g. on Turion X2 Ultra:
powernow-k8: Found 1 AMD Turion(tm)X2 Ultra DualCore Mobile ZM-82
processors (2 cpu cores) (version 2.20.00)
powernow-k8: 0 : pstate 0 (2200 MHz)
powernow-k8: 1 : pstate 1 (1100 MHz)
powernow-k8: 2 : pstate 2 (600 MHz)
But this is wrong as frequency for Pstate2 is 550 MHz. x86info reports it
correctly:
#x86info -a |grep Pstate
...
Pstate-0: fid=e, did=0, vid=24 (2200MHz)
Pstate-1: fid=e, did=1, vid=30 (1100MHz)
Pstate-2: fid=e, did=2, vid=3c (550MHz) (current)
Solution is to determine the frequency directly from Pstate MSRs instead
of using rounded values from ACPI table.
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
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- Make the message shorter and easier to grep for
- Use printk_once instead of WARN_ONCE (functionality of these was mixed)
Signed-off-by: Thomas Renninger <trenn@suse.de>
Cc: Langsdorf, Mark <mark.langsdorf@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
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* Rafael J. Wysocki (rjw@sisk.pl) wrote:
> This message has been generated automatically as a part of a report
> of regressions introduced between 2.6.28 and 2.6.29.
>
> The following bug entry is on the current list of known regressions
> introduced between 2.6.28 and 2.6.29. Please verify if it still should
> be listed and let me know (either way).
>
>
> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13186
> Subject : cpufreq timer teardown problem
> Submitter : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Date : 2009-04-23 14:00 (24 days old)
> References : http://marc.info/?l=linux-kernel&m=124049523515036&w=4
> Handled-By : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Patch : http://patchwork.kernel.org/patch/19754/
> http://patchwork.kernel.org/patch/19753/
>
(updated changelog)
cpufreq fix timer teardown in ondemand governor
The problem is that dbs_timer_exit() uses cancel_delayed_work() when it should
use cancel_delayed_work_sync(). cancel_delayed_work() does not wait for the
workqueue handler to exit.
The ondemand governor does not seem to be affected because the
"if (!dbs_info->enable)" check at the beginning of the workqueue handler returns
immediately without rescheduling the work. The conservative governor in
2.6.30-rc has the same check as the ondemand governor, which makes things
usually run smoothly. However, if the governor is quickly stopped and then
started, this could lead to the following race :
dbs_enable could be reenabled and multiple do_dbs_timer handlers would run.
This is why a synchronized teardown is required.
The following patch applies to, at least, 2.6.28.x, 2.6.29.1, 2.6.30-rc2.
Depends on patch
cpufreq: remove rwsem lock from CPUFREQ_GOV_STOP call
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: gregkh@suse.de
CC: stable@kernel.org
CC: cpufreq@vger.kernel.org
CC: Ingo Molnar <mingo@elte.hu>
CC: rjw@sisk.pl
CC: Ben Slusky <sluskyb@paranoiacs.org>
Signed-off-by: Dave Jones <davej@redhat.com>
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* Rafael J. Wysocki (rjw@sisk.pl) wrote:
> This message has been generated automatically as a part of a report
> of regressions introduced between 2.6.28 and 2.6.29.
>
> The following bug entry is on the current list of known regressions
> introduced between 2.6.28 and 2.6.29. Please verify if it still should
> be listed and let me know (either way).
>
>
> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13186
> Subject : cpufreq timer teardown problem
> Submitter : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Date : 2009-04-23 14:00 (24 days old)
> References : http://marc.info/?l=linux-kernel&m=124049523515036&w=4
> Handled-By : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Patch : http://patchwork.kernel.org/patch/19754/
> http://patchwork.kernel.org/patch/19753/
>
(re-send with updated changelog)
cpufreq fix timer teardown in conservative governor
The problem is that dbs_timer_exit() uses cancel_delayed_work() when it should
use cancel_delayed_work_sync(). cancel_delayed_work() does not wait for the
workqueue handler to exit.
The ondemand governor does not seem to be affected because the
"if (!dbs_info->enable)" check at the beginning of the workqueue handler returns
immediately without rescheduling the work. The conservative governor in
2.6.30-rc has the same check as the ondemand governor, which makes things
usually run smoothly. However, if the governor is quickly stopped and then
started, this could lead to the following race :
dbs_enable could be reenabled and multiple do_dbs_timer handlers would run.
This is why a synchronized teardown is required.
Depends on patch
cpufreq: remove rwsem lock from CPUFREQ_GOV_STOP call
The following patch applies to 2.6.30-rc2. Stable kernels have a similar
issue which should also be fixed, but the code changed between 2.6.29
and 2.6.30, so this patch only applies to 2.6.30-rc.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: gregkh@suse.de
CC: stable@kernel.org
CC: cpufreq@vger.kernel.org
CC: Ingo Molnar <mingo@elte.hu>
CC: rjw@sisk.pl
CC: Ben Slusky <sluskyb@paranoiacs.org>
Signed-off-by: Dave Jones <davej@redhat.com>
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* Rafael J. Wysocki (rjw@sisk.pl) wrote:
> This message has been generated automatically as a part of a report
> of regressions introduced between 2.6.28 and 2.6.29.
>
> The following bug entry is on the current list of known regressions
> introduced between 2.6.28 and 2.6.29. Please verify if it still should
> be listed and let me know (either way).
>
>
> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13186
> Subject : cpufreq timer teardown problem
> Submitter : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Date : 2009-04-23 14:00 (24 days old)
> References : http://marc.info/?l=linux-kernel&m=124049523515036&w=4
> Handled-By : Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Patch : http://patchwork.kernel.org/patch/19754/
> http://patchwork.kernel.org/patch/19753/
The patches linked above depend on the following patch to remove
circular locking dependency :
cpufreq: remove rwsem lock from CPUFREQ_GOV_STOP call
(the following issue was faced when using cancel_delayed_work_sync() in the
timer teardown (which fixes a race).
* KOSAKI Motohiro (kosaki.motohiro@jp.fujitsu.com) wrote:
> Hi
>
> my box output following warnings.
> it seems regression by commit 7ccc7608b836e58fbacf65ee4f8eefa288e86fac.
>
> A: work -> do_dbs_timer() -> cpu_policy_rwsem
> B: store() -> cpu_policy_rwsem -> cpufreq_governor_dbs() -> work
>
>
Hrm, I think it must be due to my attempt to fix the timer teardown race
in ondemand governor mixed with new locking behavior in 2.6.30-rc.
The rwlock seems to be taken around the whole call to
cpufreq_governor_dbs(), when it should be only taken around accesses to
the locked data, and especially *not* around the call to
dbs_timer_exit().
Reverting my fix attempt would put the teardown race back in place
(replacing the cancel_delayed_work_sync by cancel_delayed_work).
Instead, a proper fix would imply modifying this critical section :
cpufreq.c: __cpufreq_remove_dev()
...
if (cpufreq_driver->target)
__cpufreq_governor(data, CPUFREQ_GOV_STOP);
unlock_policy_rwsem_write(cpu);
To make sure the __cpufreq_governor() callback is not called with rwsem
held. This would allow execution of cancel_delayed_work_sync() without
being nested within the rwsem.
Applies on top of the 2.6.30-rc5 tree.
Required to remove circular dep in teardown of both conservative and
ondemande governors so they can use cancel_delayed_work_sync().
CPUFREQ_GOV_STOP does not modify the policy, therefore this locking seemed
unneeded.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Greg KH <greg@kroah.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: "Rafael J. Wysocki" <rjw@sisk.pl>
CC: Ben Slusky <sluskyb@paranoiacs.org>
CC: Chris Wright <chrisw@sous-sol.org>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
|
